Binaural beats and two synths

Thomas Glendinning Binaural Beat Generator

Binaural beats are those that comprise two tones at slightly different frequencies played into your ears through headphones, and this plug-in enables you to generate them. The concept might sound a bit scary, but the interface looks friendly enough.

Krakli Software Harm

Previously available as part of the RMP2 pack, this synth - which is designed for producing aggressive and strange sounds - is now available for free. It doesn't look too tricky to program, though you can avail yourself of 64 presets (created by Dimitri Schkoda) if you want to test its capabilities immediately.